AD 97-20-13 SUPERSEDED

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 97-20-13 which was sent previously to all known U.S. owners and operators of Eurocopter Deutschland Model EC135 P1 and T1 helicopters by individual letters. This amendment is prompted by the discovery of cracks on the stator blades of the fenestron tail rotor (tail rotor). The actions specified by this AD are intended to prevent failure of the tail rotor and subsequent loss of control of the helicopter.

Final rule; request for comments

97-20-13 EUROCOPTER DEUTSCHLAND: Amendment 39-10240. Docket No. 97-SW-46- AD. \n\n\tApplicability: Model EC135 P1 and T1 helicopters, certificated in any category. \n\n\tNOTE 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must use the authority provided in paragraph (d) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any helicopter from the applicability of this AD. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent failure of the tail rotor and subsequent loss of control of the helicopter, accomplish the following: \n\n\t(a)\tBefore further flight, and thereafter before the first flight of each day, visually inspect all stator blades in the stator hub area for cracks (see Figure 1). Inspect the stator blades in the areas where they are riveted to the stator hub. Pay particular attention to the radius areas where the stator blade base attaches to the stator hub. \n\n\t\t(1)\tIf the inspection reveals a crack at the base of a stator blade, remove the paint from the area and perform a dye-penetrant inspection. \n\n\t\t(2)\tIf the inspection reveals 3 or less cracked stator blades and a total crack length per stator blade of less than 15mm, stop-drill each crack with a 2mm diameter drill. \n\n\t(b)\tWithin 400 hours time-in-service (TIS), and thereafter, at intervals not to exceed 400 hours TIS, remove the paint from all stator blades in the stator hub area and perform a dye-penetrant inspection for cracks. \n\n\t(c)\tIf the inspections reveal cracks on any stator blade with a total crack length of 15mm or longer, or if more than 3 stator blades are cracked, remove the affected stator blades and replace them with airworthy stator blades before further flight. The inspections required by this AD must continue to be performed on all stator blades including replacement stator blades. \n\n\tNOTE 2: Eurocopter Deutschland Alert Service Bulletin No. EC 135-53A-001, Revision 01, dated August 8, 1997, pertains to this AD. \n\n\t(d)\tAn alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Rotorcraft Standards Staff, Rotorcraft Directorate, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who mayconcur or comment and then send it to the Manager, Rotorcraft Standards Staff. \n\n\tNOTE 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff. \n\n\t(e)\tSpecial flight permits will not be issued. \n\n\tNOTE 4: The subject of this AD is addressed in Luftfahrt-Bundesamt (Germany) AD 97-249, effective September 25, 1997. \n\n\t(f)\tThis amendment becomes effective on December 29, 1997, to all persons except those persons to whom it was made immediately effective by Priority Letter AD 97-20-13, issued September 25, 1997, which contained the requirements of this amendment.

On September 25, 1997, the FAA issued priority letter AD 97-20-13, applicable to Eurocopter Deutschland Model EC135 P1 and T1 helicopters, which requires immediate and daily repetitive inspections of the stator blades for cracks in the stator hub area. If this visual inspection reveals a crack, a dye-penetrant inspection is required. Also, within 400 hours time-in-service (TIS) after the effective date of this AD, and thereafter, at intervals not to exceed 400 hours TIS, a dye-penetrant inspection for cracks is required. If any of the inspections reveal cracked stator blades, each crack must be stop-drilled. If any of the inspections reveal cracks on a stator blade with a total crack length of 15mm or longer, or if cracks are found on more than 3 stator blades, the affected blades must be replaced with airworthy blades prior to further flight. That action was prompted by the discovery of cracks on the stator blades of the tail rotor. This condition, if notcorrected, could result in failure of the tail rotor and subsequent loss of control of the helicopter.\n\n Since the unsafe condition described is likely to exist or develop on other Eurocopter Deutschland Model EC135 P1 and T1 helicopters of the same type design, the FAA issued priority letter AD 97-20-13 to prevent failure of the tail rotor and subsequent loss of control of the helicopter. The AD requires, before further flight, and thereafter, before the first flight of each day, visually inspecting the stator blades in the stator hub area. If this visual inspection reveals a crack, a dye-penetrant inspection is required. Also, within 400 hours TIS after the effective date of this AD, and thereafter, at intervals not to exceed 400 hours TIS, a dye-penetrant inspection for cracks is required. If any of the inspections reveal cracked stator blades, each crack must be stop-drilled. If any of the inspections reveal cracks on a stator blade with a total crack length of 15mm or longer, or if cracks are found on more than 3 stator blades, the affected stator blades must be replaced with airworthy stator blades prior to further flight.\n\n Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual letters issued on September 25, 1997 to all known U.S. owners and operators of Eurocopter Deutschland Model EC135 P1 and T1 helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons.\n\nComments Invited\n Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.\n\n Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizeseach FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.\n\n Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 97-SW-46-AD." The postcard will be date stamped and returned to the commenter.\n\n The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \n\n The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."\n\nList of Subjects in 14 CFR Part 39 \n Air transportation, Aircraft, Aviation safety, Safety.\n\nAdoption of the Amendment\n Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:\n\nPART 39 - AIRWORTHINESS DIRECTIVES \n 1. The authority citation for part 39 continues to read as follows: \n Authority: 49 USC 106(g), 40113, 44701.\n\n§ 39.13 - (Amended)\n 2. Section 39.13 is amended by adding a new airworthiness directive to read as follows:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Office of Regional Counsel, Southwest Region, Attention: Rules Docket No. 97-SW-46-AD, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.

Mr. Richard Monschke, Aerospace Engineer, FAA, Rotorcraft Directorate, Rotorcraft Standards Staff, 2601 Meacham Blvd., Fort Worth, Texas 76137, telephone (817) 222-5116, (817) 222-5961.